During the past decade, many researchers have been intrigued by the prospect of building electronic circuits based on molecular or molecular-scale components. The potential of molecular electronics has been to bring the power of synthetic chemistry to the electronics industry by creating purpose-built devices that may be able to at least partially assemble themselves into useful circuits. This prospective has led to a significant number of studies of the electronic properties of molecules and the demonstration of some proof-of-principles of memory and logic circuits.
Studies of switching in nanometer-scale crossed-wire devices have previously been reported that could be switched reversibly and had an ON-to-OFF conductance ratio of 104. These devices have been used to construct crossbar circuits and provide a promising route for the creation of ultra-high density nonvolatile memory. A series connection of cross-wire switches that can be used to fabricate a latch has also been demonstrated; such a latch is an important component for logic circuits and for communication between logic and memory. New logic families that can be constructed entirely from crossbar arrays of switches or as hybrid structures composed of switches and transistors have been described. These new logic families have the potential to dramatically increase the computing efficiency of CMOS circuits, thereby enabling performance improvements of orders of magnitude without having to shrink transistors, or to even replace CMOS for some applications if necessary. However, it is desired to improve the performance of the devices that are presently fabricated, especially their cyclability.